Added "network" option to DeviceEvents
Added "network" option to DeviceEvents

- Needed to record metadata on network requests made using BMSCore APIs

ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics-api,ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics-api,ibm-bluemix-mobile-services/bms-clientsdk-swift-analytics-api